JPH0621842B2 - Wind tunnel wind speed controller - Google Patents

Description

TECHNICAL FIELD The present invention relates to a wind speed control device for a wind tunnel.

BACKGROUND ART Wind tunnels are widely used as a means for investigating the aerodynamic characteristics of structures such as bridges and high-rise buildings. Wind tunnels are also used to study the aerodynamic performance of vehicles and flying objects. Furthermore, wind tunnels are also used to simulate atmospheric and meteorological conditions. Generally, when the survey object is large, a scale model is used, and when the survey object is small, the real thing is used for the test.

The equipment of the wind tunnel is basically (a) an air flow source that is a blower that causes an air flow, (b) an air conditioner that adjusts the temperature and humidity of the air, and (c) an object to be investigated. A measuring unit for installing a test object, (d) a measuring device provided in the measuring unit for measuring the aerodynamic performance of the object of investigation, and (e) limiting the air flow spatially and making the flow uniform. And (f) a controller for adjusting the air source and the air conditioner to obtain a predetermined air flow condition. A wind speed control device further provided with a main damper for controlling the amount of air supplied from the air conditioner to the measuring unit and a bypass damper for branching and bypassing the air from the air conditioner, for example 57-14943 and JP-A-59-69
817 and the like. The present invention relates to a wind speed control device for adjusting the wind speed among the control devices in such a wind tunnel.

In such a conventional wind speed control device for a wind tunnel, the degree of automation is low, and the wind speed control device itself is composed of a case, an operational amplifier, a signal selector, and the like, and individually inspects each component part thereof. I was able to. In recent years, sophisticated technology has been required, and therefore, the wind speed control device has become computerized, has a high degree of automation, and is performing complicated processing. Furthermore, instead of the operation of each component part, the computer Internal processing is being performed, and it is becoming impossible to inspect each component part individually. Moreover, the output of the machine is increasing. On the other hand, the quality of workers who operate the wind tunnel tends to deteriorate. In such a situation, if an abnormality occurs in the wind speed control device, the effect is small if the degree of automation is low as in the past or the output of the machine is small, but as in recent years, the wind speed control device is As it becomes more complex and the power to handle it increases, the impact will be great, leading to equipment damage and personal injury. Therefore, if an abnormality or malfunction occurs in the wind speed control device, it is required to detect it as soon as possible and promptly take appropriate measures.

In a typical prior art, a deviation between the wind speed command value and the actual wind speed detection value, that is, a control error is monitored, and when the deviation is large, it is determined that the wind speed control device is abnormal. While such a configuration has the advantages of being simple and inexpensive, it is not always possible to correctly detect an abnormality. For example, when the wind speed command value greatly changes, the deviation is large immediately after that, and the deviation becomes smaller with time. Even in such a normal condition, if the detection is made only by the magnitude of the deviation, a wrong judgment will be made.

Conventionally, the strength of the wind pipe and the strength of the damper are sufficient, and even if the main damper is fully closed when the blower is rotating at high speed, the wind pipe may burst or the main damper may be damaged. However, as the power handled in recent years has increased, such strength is becoming insufficient.

In a wind tunnel, the capacity or capacity of the blower is generally selected to be larger than the rated wind speed of the equipment in consideration of the acceleration / deceleration capacity. In such a situation, if the Pitot tube that detects the wind speed is clogged with foreign matter, the pressure tube that connects the Pitot tube and the differential pressure detector is disconnected, or the signal line connected to the differential pressure detector is disconnected, Since the actual wind speed is determined to be zero, the rotation speed of the blower is increased to the limit of its capacity. In other words, the blower is operated beyond the capacity of the facility. Therefore, the air duct and blower body are damaged. Further, in the measuring section provided with the object to be tested, the object to be tested is damaged. Furthermore, such troubles that occur without notice endanger the workers working in the measuring section and lead to personal injury.

Problem to be Solved by the Invention An object of the present invention is to provide a wind speed control device for a wind tunnel capable of preventing damage to components of the wind tunnel, such as rupture of a wind pipe and breakage of a damper.

Another object of the present invention is to prevent the blower from being accelerated beyond the capacity of the equipment of the wind tunnel to prevent damage to the components of the wind tunnel and to prevent personal injury. An object is to provide a wind speed control device.

Still another object of the present invention is to provide a wind speed control device for a wind tunnel, which is capable of detecting an abnormality when it occurs and preventing damage to equipment or personal injury in advance.

Means for Solving the Problem The present invention is a wind speed control device for a wind tunnel that blows air from a blower to an object under test through a wind pipe provided with a damper, and detects a rotation speed of the blower. Means, an actual wind speed detecting means provided on the downstream side of the damper for detecting the actual wind speed of the blown air, and a rotation speed detected by the rotation speed detecting means is the first
And comparing the fact that the actual wind speed detected by the actual wind speed detecting means is greater than or equal to the second predetermined value. A wind speed control device for a wind tunnel, comprising: a second comparing means for controlling the opening of the damper in response to a comparison output of at least one of the first and second comparing means. is there.

Further, the present invention is a wind speed control device for a wind tunnel that blows air from a blower to an object to be tested through a wind pipe provided with a damper, which is provided on the upstream side of the damper and detects pressure of air. Means and a comparing means for comparing and detecting that the pressure detected by the pressure detecting means exceeds a predetermined value, and the opening degree of the damper is greatly changed in response to the comparison output of the comparing means. And a wind speed control device for the wind tunnel.

Further, the present invention is a wind speed control device for a wind tunnel that blows air from a blower to an object to be tested through a wind pipe provided with a main damper, wherein a bypass duct is provided upstream of the main damper. By installing a bypass damper linked to the main damper, and installing a flowmeter upstream of the main damper and the bypass damper, comparing that the flow rate detected by the flowmeter exceeds a predetermined value. A wind speed control device for a wind tunnel, comprising: comparing means for detecting; and means for greatly changing the opening of the main damper in response to a comparison output of the comparing means.

Further, the present invention, in the wind speed control device of the wind tunnel that blows air from the blower to the object to be tested through the wind tube, means for generating a command value of the rotation speed of the blower, and the command value, the command value And a means for limiting to an upper limit value selected within a range less than a predetermined value that is equal to or higher than the maximum possible rotation speed of and that causes damage to the equipment, and the output of the limiting means is given to the blower. It is a wind tunnel wind speed control device.

Further, the present invention is a wind speed control device for a wind tunnel that blows air from a blower through a wind pipe provided with a damper onto an object under test, a rotation speed detecting means for detecting the rotation speed of the blower, and a damper Detected by comparing the actual wind speed detecting means provided on the downstream side for detecting the actual wind speed of the blown air with the fact that the rotation speed detected by the rotation speed detecting means becomes equal to or higher than the first predetermined value. First to do
Both the first comparing means and the second comparing means for detecting by comparing the actual wind speed detected by the actual wind speed detecting means with the actual wind speed being less than a second predetermined value. And a means for stopping the blower when a comparative output is obtained.

Further, the present invention is, in a wind speed control device of a wind tunnel that blows air from a blower to an object to be tested through a wind tube, a rotation speed detection unit that detects a rotation speed of the blower, and is provided downstream of a damper. An actual wind speed detecting means for detecting the actual wind speed of the blown air; a subtracting means for obtaining a difference between an output of the rotation speed detecting means and a normal rotation speed corresponding to the output of the actual wind speed detecting means; A wind speed control device for a wind tunnel, comprising means for stopping the blower when the absolute value of the difference is equal to or more than a predetermined value in response to the output.

Operation According to the present invention, when the rotation speed detected by the rotation speed detection means of the blower becomes equal to or higher than the predetermined value, or the object to be tested detected by the actual wind speed detection means is provided. When at least one of the phenomena occurs when the actual wind speed in the measuring unit or the like is equal to or higher than the second predetermined value, the opening degree of the damper is greatly changed and the opening degree is, for example, fully opened. This prevents the air accelerated at a high speed in the blower from being dammed by the damper to prevent the air pressure on the upstream side of the damper from rising abnormally. As a result, the wind pipe and the damper are subjected to a strong force and are prevented from being damaged.

Further, according to the invention, the pressure detecting means for detecting the pressure of the air is provided on the upstream side of the damper, and when the detected pressure exceeds a predetermined value, the opening degree of the damper is greatly changed. This prevents its pressure rise and prevents damage to the wind tunnel.

Further, according to the present invention, the air from the blower is guided to the measurement unit where the object to be tested is provided via the main damper, and a part of the air from the blower is branched via the bypass damper. It is possible to provide a flow meter on the upstream side of the main damper and the bypass damper, and when the flow rate detected by the flow meter exceeds a predetermined value, that is, when the blower has a large flow rate at the maximum rotation speed, for example. When an abnormal state in which air is supplied at a high speed is reached, the opening of the main damper is greatly changed to, for example, fully open. This prevents damage to the wind tunnel components.

Further, according to the present invention, the command value of the rotation speed of the blower is equal to or higher than the maximum possible rotation speed of the command value and is less than a predetermined range until the equipment of the wind tunnel, for example, the wind pipe and the damper is destroyed. Limit to the upper limit selected in. This prevents the rotational speed of the blower from rising abnormally, prevents damage to the wind tunnel, and maintains safety.

Furthermore, according to the present invention, when the rotation speed of the blower is equal to or higher than the first predetermined value and the actual wind speed is less than the second predetermined value, the blower is stopped to ensure safety. Secure. The rotation speed of the blower and the actual wind speed obtained thereby are approximately directly proportional to each other in the normal state.
Therefore, when the actual wind speed is low despite the high rotation speed, it can be determined that an abnormality has occurred, and in such a case, the blower is stopped.

Further, according to the invention, the difference between the rotation speed of the blower and the rotation speed at the normal time corresponding to the detected actual wind speed is obtained, and when this difference is large, it is determined that an abnormality has occurred, and the blower is detected. Stop and secure your safety. The difference between the actual wind speed detected by the actual wind speed detection means and the normal wind speed corresponding to the rotation speed of the blower rotated by the rotation speed detection means is obtained, and the absolute value of the difference is calculated in advance. The blower may be stopped when it is determined to be abnormal when the value exceeds a predetermined value, and such a configuration is included in the spirit of the present invention described in the above-mentioned claims.

Embodiment FIG. 1 is an overall block diagram of an embodiment of the present invention. In the low wind speed region, the blower 2 is used based on the wind speed set value Vsoll from the chassis dynamo 1 which is the wind speed setting means.
The motor 3 for driving the motor 3 is rotationally controlled at a constant speed corresponding to the minimum wind speed setting value Cmin from the minimum wind speed setting circuit 4. At this time, the main damper 5 and the bypass damper 21 are controlled by the feedforward control circuit 6. Then feed forward control is performed. In the high speed region of the wind speed, the negative feedback control for driving the blower 2 is performed by the proportional and integral (abbreviated as PI) control circuit 8 based on the measured wind speed value Vist from the means 7 for detecting the actual wind speed. In order to improve the response speed of the actual wind speed, that is, the wind speed set value Vso which is the output from the chassis dynamo 1.
In order to improve the followability of the actual wind speed Vist with respect to ll, it is controlled by the feedforward control circuit 9.

FIG. 2 is a diagram showing the overall configuration of the wind tunnel. The entire air duct is covered by the air duct 10, and the blower 2 is installed inside the air duct 10.
Is installed. The blower 2 is driven by the motor 3 as described above. The motor 3 may be directly connected to the blower 2 or may be configured to be driven via a belt hook or a gear train. An air conditioner 11 is provided downstream of the blower 2. The air conditioner 11 has a heat exchanger that guides hot water to exchange heat with the air in order to adjust the temperature of the air flow, and in some cases, for example, room temperature water is supplied instead of the hot water. A guide vane 12 is provided in the air duct 10. The measurement unit 13 that performs the measurement experiment includes an object to be tested,
For example, a vehicle 14 is placed and a nozzle 15 for forming an air flow is arranged in the front. The measurement unit 13 is provided with a heater 16 that produces road surface heat, a heater 17 that produces solar heat, and the like, and can form a thermal equilibrium state together with the air conditioner 11. A bell mouth 18 is provided downstream of the measuring unit 13, and the flow of air diffused by the measuring unit 13 is drawn into the air duct again. In addition to the open type in which the measuring unit 13 is open as shown in FIG. 2, the measuring unit 13 itself may be a closed type wind tunnel covered with a wind pipe. When it is a closed type wind tunnel, instead of the nozzle 15, an airflow restrictor called a contraction section,
And a predetermined condition forming means for obtaining the local uniformity of the wind speed is provided and covered by the housing 19.

The air sucked into the bell mouth 18 is supplied to the blower 2 again. Such a wind tunnel is called a circulation type wind tunnel. In addition, the air discharged from the blower 2 may be in the form of a wind tunnel that is discharged to the atmosphere and is not supplied to the blower 2 again.

A main damper 5 is provided between the air conditioner 11 and the measuring unit 13, and a bypass duct 20 is provided in front of the main damper 5. The other end of the bypass duct 20 is connected to the wind pipe 10 on the downstream side of the measurement unit 13, and a bypass damper 21 is arranged near the inlet of the bypass duct 20. The main damper 5 and the bypass damper 21 are openable / closable, and the air passage cross-sectional areas of the main air passage air duct 10a and the bypass duct 20 can be adjusted respectively.
These dampers 5 and 21 are configured to be interlocked by a double-acting hydraulic cylinder 22 as shown in FIG.
The main damper 5 is as shown in FIG. 3 (1), and the bypass damper 21 is as shown in FIG. 3 (2). When the main damper 5 is closed, the bypass damper 21 is opened, and when the bypass damper 21 is closed, the main damper 5 is opened.

The bypass duct 20 is installed to improve the airflow performance at low wind speeds, particularly the performance of wind speed control.
The bypass duct 20 is also used to maintain a thermal equilibrium state. Depending on the purpose of the experiment in the measuring unit 13, the bypass duct 20 and the bypass damper 21 may be omitted.

The drive wheels of the vehicle 14, which is the object to be measured, provided in the measurement unit 13 drive the chassis dynamo 1 provided on the floor, whereby the speed corresponding to the wheels, that is, the output corresponding to the vehicle speed, It is derived as the aforementioned wind speed set value Vsoll.

In order to measure the wind speed in the measuring part 13, a Pitot tube 23 connected in association with the differential pressure detector is provided, and the temperature of the air supplied to the measuring part 13 is detected by a thermometer 24. It The outputs from the Pitot tube 23 and the thermometer 24 are given to the wind speed calculation circuit 25, and thus the actual wind speed V
ist is calculated based on the first equation.

Here, kv is a constant, te is a temperature measured by the thermometer 24, and ΔP is a dynamic pressure detected by the pitot tube 23. Pitot tube 23, thermometer 24, and wind speed calculation circuit 2
5 constitutes the wind speed detection means 7.

A signal representing the actual wind speed Vist is derived from the wind speed calculation circuit 25 on the line 26, and the characteristic imparting circuit 5 is supplied from the subtraction circuit 27.
6 and line 28 to subtraction circuit 29.

The wind speed set value Vsoll from the chassis dynamo 1 is given to the subtracter 29 from the line 34 via the characteristic giving circuit 32. Signal from line 34 and line 28
From the line 35, the deviation ε from the signal passing through the characteristic imparting circuit 56 is obtained from the PI control circuit 8 for feedback control from the line 35.
To the adder circuit 3 from the line 36.
The addition output MV0 is led to the line 38 via 7.
The signal MV0 on the line 38 is supplied to the adder circuit 39. The output Cmin from the minimum rotation speed setting circuit 4 is given to the adding circuit 39 as described above, and the rotation speed setting value Nsoll thus obtained is supplied from the line 40 through the limiting circuit 60 and the switch 61 to the motor drive circuit 41. Given to.

The motor drive circuit 41, which is a means for controlling the rotation speed of the blower, includes a subtractor 42, a rotation speed control circuit 44, and a rotation speed detector 45 for detecting the rotation speed of the motor 3 so as to perform feed back control. Is composed of. Thus, the blower 2 is controlled by the rotation speed setting value Nsoll.

The signal SV0 from the line 34 is given to the feedforward control circuit 9, and its output FF is inputted to the adder 37, and thus the feedforward control of the blower 2 is performed according to the motor 3.

The signal Vsoll from line 30 is applied to the feedforward control circuit 6 for the damper 5 and its output SV
d is given to the function generating circuit 46, a signal representing the opening degree θ of the damper 5 corresponding to the input SVd is derived to the line 47, and given from the switch 62 to the damper opening control circuit 48.

The damper opening control circuit 48 includes a subtractor 49, a servo controller 50, an electrohydraulic servo valve 51, and a detector 52 that detects the opening of the main damper 5, and outputs the electrohydraulic servo valve 51. Thus, the hydraulic cylinder 22 is double-actuated, the main damper 5 is controlled to an opening degree corresponding to the output θ of the function generating circuit 46, and the bypass damper 21 is also driven accordingly.

The function generator circuit 46 opens the opening θ of the main damper 5 as the output SVd of the feedforward control circuit 6 increases.
Has an increasing characteristic, which is as shown in FIG. Thus, the opening θ of the main damper 5 is determined by the signal SVd.
Is calculated directly based on. Therefore, as shown in FIG. 5 (1), as the speed of the vehicle 14 (that is, the vehicle speed), and accordingly the wind speed set value Vsoll, increases, as shown in FIG. 5 (1), the main damper 5 increases. When the vehicle speed is 40 km / h or more, the opening becomes 100%. Further, the rotation speed of the motor 3 for driving the blower 2 is as shown in FIG.
4, therefore the wind speed set value Vsoll is 0 to 35.
In the range of less than km / h, the value is Cmin set by the minimum rotation speed setting circuit 4, and when the vehicle speed is 35 km / h or more, the rotation speed of the motor 3 is increased in accordance with the increase of the signal Vsoll. To be done. Wind speed 35-40km
In the range of / h, both the main damper 5 and the blower 2 are controlled, and a smooth change in the wind speed in the measurement unit 13 is achieved.

In order to control the blower 2, the signal Vso on the line 30
11 is supplied to the subtractor 31 as described above, and the subtractor 31 outputs the output SVmi from the lower limit wind speed setting circuit 55.
n is given. The signal SVmin output from the lower limit wind speed setting circuit 55 is a value corresponding to the vehicle speed of 35 km / h described with reference to FIG. The subtractor 31 calculates the output SV1 (= Vsoll-SVmin) and supplies it to the characteristic imparting circuit 32. This characteristic imparting circuit 32
As shown in FIG. 6, when the output SV1 of the subtractor 31 is negative, an output that is zero is derived, and when the output of the subtractor 31 is zero or more, the output SV1 is amplified with an amplification factor of 1. Derive. In this way, the blower 2 has the wind speed SVmin.
Below (for example, a value corresponding to a vehicle speed of 35 km / h), the output of the characteristic imparting circuit 32 is zero, and the motor 3 has a rotational speed Cmin set by the minimum rotational speed setting circuit 4.
Will be controlled at a constant rotation speed.

In this way, in the low wind speed range where the vehicle speed is 40 km / h or less,
The opening of the damper 5 is adjusted to adjust the wind speed in the measuring unit 13, which prevents malfunction due to difficulty in generally detecting the wind speed with low accuracy and high accuracy, and the low rotation speed range of the motor 3. The instability of the operation due to the low stability of the inverter included in the control circuit 44 that drives the motor 3 at low frequency is prevented. At a vehicle speed of 40 km / h or more, the damper 5 is fully opened, and the rotation speed of the motor 3 that drives the blower 2 is stably controlled.

The output of the lower limit wind speed setting circuit 55 is also given to the subtractor 27, and the output of this subtractor 27 is the above-mentioned characteristic giving circuit 32.
Is given to the characteristic imparting circuit 56 having the same configuration as described above, whereby the output derived from the characteristic imparting circuit 56 to the line 28 is zero when the wind speed is less than the lower limit value SVmin.

The rotation speed control circuit 44 may have an inverter, but may be configured to control the rotation moderation of the motor 3 by another configuration.

A power amplifier circuit and a servomotor may be used instead of the double-acting hydraulic cylinder 22 that drives the dampers 5 and 21 and the electrohydraulic servo valve 51, or may be realized by another configuration.

In order to prevent the wind tube 10 from rupturing and prevent the main damper 5 from being damaged, it is further configured as follows. The rotation speed of the blower 2 is detected by the detection means 45, and its output Nist is the first
It is given to the comparison circuit 63. The characteristic of the first comparison circuit 63 is as shown in FIG. 7, and the first detected value N1 of the input detected rotational speed Nist is predetermined.
When the value is less than the predetermined value N2, the output is low level, that is, logic "0", and when the input Nist is the value N2 or more, it is high level, that is, logic "1". The first predetermined value N1 corresponds to the level of the output SVd of the feedforward circuit 6 described above for the main damper 5 to be fully opened, that is, to have the opening of 100%.

Actual wind speed Vi derived from the wind speed detecting means 7 to the line 26
The signal indicating st is provided to the second comparison circuit 64. The second comparison circuit 64 has a configuration similar to that of the first comparison circuit 63 described above, and the actual wind speed Vist is equal to or greater than a second predetermined value N1 corresponding to the value Cov at which the main damper 5 is fully opened. Below the defined value N2, the output is low level,
It is at a high level above N2.

The outputs of the first and second comparison circuits 63 and 64 are given to the OR gate 65, and the outputs of the OR gate 65 cause the contacts 62a and 62b of the switch 62 to change their switching modes. When the output of the OR gate 65 is high level, the contact 62a is conductive, and the contact 62b is cut off. When the output of the OR gate 65 is low level, the contact 62a is closed.
a is cut off, and the contact 62b is made conductive. The contact 62a includes
A signal for causing the main damper 5 to be fully opened is generated from the fully open command circuit 66.

At low wind speed, the output of the OR gate 65 is at a low level, so that the contact 62b becomes conductive, and the output θ of the function generating circuit 46 becomes.
Is used as an opening command for the dampers 5, 21. When the rotation speed Nist of the blower 2 is less than the value N2 set by the first comparison circuit 63 or when the actual wind speed Vist is less than the predetermined value set by the second comparison circuit 64,
The outputs of the first and second comparison circuits 63 and 64 are at the low level, so that the wind speed control is performed by the dampers 5, 21.
In a relatively low wind speed range adjusted by the opening of
The output of the gate 65 is low level.

When the rotation speed Nist of the blower 2 is equal to or higher than a predetermined value N2 or when the actual wind speed Vist is equal to or higher than a predetermined value set by the second comparison circuit 64, at least one of the first and second comparison circuits 63, 64 From which a high level signal is derived, and the output of the OR gate 65 becomes a high level. Therefore, the contact 62a of the switch 62 is made conductive and the contact 62b is cut off. As a result, as for the damper opening command signal, the full-open command value is derived from the circuit 66. Therefore, regardless of the wind speed command value Vsoll, that is, regardless of the output θ of the damper characteristic, the main damper 5 is fully opened and bypassed. The damper 21 is fully closed.

In the first and second comparison circuits 63 and 64, the rotation speed N
Discrimination level N with which ist and actual wind speed Vist are compared
2 and the like are selected to be values larger than the value N1 at which the main damper 5 is fully opened, that is, the value corresponding to the value Cov, and as a result, the control system is affected while the wind speed control device is operating normally. Don't give.

Now, when the main damper 5 is fully open during operation at high wind speed, the wind speed command value Vsoll suddenly drops, and if the line leading to the wind speed command value Vsoll is lost due to disconnection or the like, the main damper 5 is lost. Since the program control by the feed forward circuit 6 is performed, the control is performed so that the opening corresponds to the wind speed command value. On the other hand, the wind speed command value Vs
Even if ol suddenly decreases, the rotation speed of the blower 2 does not suddenly decrease due to the moment of inertia of the blower 2 and the motor 3. Further, the wind speed of the air in the air duct inside the wind pipe 10 accelerated to a high wind speed does not immediately decrease due to its inertia. Therefore, if the first and second comparison circuits 63 and 64, the OR gate 65, the switch 6
2 and the full-open command circuit 66 do not exist, the main damper 5 becomes a command that the command value θ from the function generating circuit 46 is fully closed, even though the actual wind speed does not decrease. The damper 5 is closed completely. When such a situation occurs, the air accelerated at a high speed is dammed by the main damper 5, and the pressure of the air on the upstream side of the damper 5 rises abnormally. As a result, the wind pipe 10 and the main damper 5 receive a strong force and are eventually broken. The embodiments described above prevent such problems. That is, the rotation speed Nist
Alternatively, the actual wind speed Vist is the first and second comparison circuits 63,
When it is a large value equal to or larger than the value N2 set in 64, the OR gate 65 is irrelevant regardless of the wind speed command value Vsoll.
Since the output of is at a high level, the main damper 5 is fully opened, the air on the upstream side of the main damper 5 is not stopped by the main damper 5, damage is prevented, and safety is secured. .

Since the pitot tube 23 is provided on the downstream side of the main damper 5,
When the main damper 5 is fully closed, it becomes impossible to detect the actual wind speed. Therefore, the rotation speed Nist of the blower 2 is compared in the first comparison circuit 63 as described above, and damage is prevented and safety is ensured as described above.

Next, the actual wind speed Vist detected by the wind speed detecting means 7 is detected because the pitot tube 23 fails or the pressure tube of the differential pressure detector connected to the pitot tube 23 is disconnected. Even when a malfunction occurs due to zero,
A limiting circuit 60 is provided to prevent the rotation speed of the blower 2 from increasing abnormally high. This limiting circuit 6
The rotation speed command value Nsoll is given to one input of 0, and the upper limit value NS which is the maximum allowable value from the upper limit value setting circuit 67 is given to the other input. This upper limit NS
Is a value equal to or higher than the maximum possible rotation speed of the rotation speed command value Nsoll, and is a facility, for example, the wind pipe 10.
And the main damper 5 and the like are destroyed within a range less than a predetermined value, for example 120% of the rated rotation speed.
May be a value of.

FIG. 8 is an electric circuit diagram showing a specific configuration of the limiting circuit 60. The rotation speed command value Nsoll and the upper limit value NS are given to one input of the operational amplifier circuit 71 through the diodes 69 and 70 and further through the resistors R1 and R2. The resistor R3 is connected to the operational amplifier circuit 71, and the resistor R4 is connected to another input terminal. Resistance R
The resistance values of 1, R2 and R3 are the same. Therefore, the command value derived from the limiting circuit 60 to the line 70 is derived by selecting the smaller signal value of the rotation speed command value Nsoll and the upper limit value NS. The upper limit NS is the blower 2 corresponding to the maximum wind speed determined by the facility capacity as described above.
Is the rotation speed of. In the limiting circuit 60, as described above, the signal having the smaller value of the two inputs Nsoll and the upper limit NS is
The output is led to line 72. Limiting circuit 60
May be realized by a computer or the like. Upper limit N
Since S is set to the maximum allowable value of the equipment, the rotation speed command value Nsoll is normally selected, and the presence of the limiting circuit 60 does not affect the control system.

When an abnormality occurs in the wind tunnel equipment and the rotation speed command value Nsoll becomes abnormally large, the limiting circuit 60 works effectively. Due to the operation of the limiting circuit 60, the rotation speed command value of the signal derived on the line 72 does not exceed the upper limit value NS, and therefore the wind speed does not become abnormally high. That is, the wind pipe 10 is prevented from being broken, the vehicle 14 or the like as the object to be tested in the measuring unit 13 is not damaged, and a personal injury is prevented in advance.

The reasons why the rotation speed command value Nsoll increases beyond the capacity of the equipment are as follows. For example, Pitot tube 2
3 is clogged with foreign matter, the pressure tube connecting the Pitot tube 23 and the differential pressure detector connected thereto is disconnected, or the wind speed detecting means 7 has a malfunction. In such a case, the actual wind speed Vist is erroneously detected to be small, and therefore the rotation speed command value Nsoll becomes an abnormally large value. That is, the blower 2 is accelerated and the wind tube 1
The air in 0 is further accelerated.

Further, the reason why the rotation speed command value Nsoll becomes abnormally large is that the air resistance of the measuring unit 13 is large, and accordingly, a control error, that is, a large offset amount occurs, and this offset amount is stored in the PI control circuit 8. The output MV, and thus the rotation speed command value Nsoll, accumulated by the provided integrating circuit increases with time,
This is the case when the facility capacity is exceeded. Even in such a case, the function of the limiting circuit 60 and the like prevents damage to the equipment and ensures safety.

Furthermore, in the present wind speed control device, when the above-mentioned trouble occurs and other troubles occur,
If an abnormality occurs, it is detected as early as possible to prevent equipment damage and personal injury, and is further configured as follows. Actual wind speed Vi detected by the wind speed setting means 7
st is given to the subtraction circuit 75, and the set value Cov from the setting circuit 76 is given to the subtraction circuit 75.

Cov = Vist (2) This set value Cov is a value corresponding to the command value θ for fully opening the main damper 5 as described above. The output of the subtraction circuit 75 is input to the third comparison circuit 77. In the comparison circuit 77, as shown in FIG. 9 (1), when the output of the subtraction circuit 75 is negative, the comparison output is low level, and when it is zero or more, it is high level. Therefore, when the actual wind speed Vist is less than the value corresponding to the value Cov, the output of the third comparison circuit 77 is at the high level, and thus the actual wind speed Vist is small, and thus the main damper 5 is used. Then, under the condition that the wind speed is controlled, the third comparison circuit 77 derives a high level signal.

The rotation speed Nist of the blower 2 detected by the rotation speed detection means 45 is given to another subtraction circuit 78. In the subtraction circuit 78, the value NK calculated by the coefficient unit 79 from the value Cmin from the minimum rotation speed setting circuit 4 is calculated.
Is derived on line 80 and applied to subtraction circuit 78.

NK = KIN · Cmin (3) where KIN is the gain of the coefficient unit 79. The fourth comparison circuit 80 has the same configuration as the third comparison circuit 77 described above, derives a low level signal when the output of the subtraction circuit 78 is negative, and outputs a high level signal when it is zero or more. Derive. The outputs of the third and fourth comparison circuits 77 and 80 are AN
It is fed to the D-gate 81, the output of which is delayed by a timer 83 which sets a time of 5 to 20 seconds.
1 is controlled. The timer 83 derives the output of the AND gate 81 with a delay as described above, and the time may be, for example, about 10 seconds. When the output of the timer 83 is at a low level, the contact 61b of the switch 61 is conductive and the contact 61a is closed, as shown in FIG. When the output of the timer 83 is delayed and brought to a high level based on the output of the AND gate 81 and is derived, the contact 61b is cut off and the contact 61a is made conductive. By the conduction of the contact 61a, a signal from the stop command signal generation circuit 84 for stopping the blower 2 and thus the rotation speed of the motor 3 is given to the motor drive circuit 41.

In a normal state, the rotation speed Nist of the blower 2 and the actual wind speed Vist have a substantially direct proportional relationship as shown in FIG. 9 (2), and when such a situation is not achieved, the present wind speed control is performed. It is determined that an abnormality has occurred in the device, and the blower 2 is stopped.

The value Cov set in the setting circuit 76 corresponds to the fully open value wind speed set value of the main damper 5. The minimum rotation speed Cmin is the rotation speed of the blower 2 at this value Cov.

In the region where the wind speed control is adjusted by the rotation speed of the blower 2, the relationship of Vist> Cov ... (4) is established. At this time, the output of the third comparison circuit 77 is at low level. At this time, regardless of the output of the fourth comparison circuit 80, the output of the AND gate 81 is at a low level, so that the contact 61b of the switch 61 is conductive, the contact 61a is cut off, and the tripper that stops the blower 2 is tripped. No signal is being emitted.

When the wind speed control is in a region controlled by the opening of the main damper 5, that is, Vist <Cov ... (5), the output of the third comparison circuit 77 becomes high level, and the output of the AND gate 81 becomes the fourth output. It is determined by the output of the comparison circuit 80. That is, the minimum rotation speed Cmin
Is multiplied by the gain Kin set by the coefficient unit 79,
It is as in the third equation and is given to the subtraction circuit 78. The fourth comparison circuit 80 determines whether the input signal from the subtraction circuit 78 is positive or negative, and when it is positive, that is, when the rotation speed Nist is high, derives a high-level signal.

Next, when Nist = Cmin (6), Vist = Cov (7). The values Cmin and Cov are predetermined so that such a condition is satisfied. Gain kin
Is set to a value greater than 1, Nist <KIN · Cmin (8) is always satisfied in the region where the above-mentioned fifth formula is satisfied. That is, when the output of the third comparison circuit 77 is at the high level, the output of the fourth comparison circuit 80 is always at the low level, the contact 61b of the switch 61 is conductive, and the trip signal is not transmitted. In other words, when all the wind speed control devices are operating normally,
No trip signal is generated.

Here, the pitot tube 23 for detecting the wind speed is clogged with foreign matter, the pressure tube connecting the pitot tube and the differential pressure detector is damaged, the signal of the differential pressure detector is disconnected, and the actual wind speed Vist becomes When the value is abnormally low, the contact 61a of the switch 61 becomes conductive and a trip signal for stopping the blower 2 is output. That is, when such an abnormality occurs, since the actual wind speed Vist is small, the above-mentioned fifth equation is established, and the output of the third comparison circuit 77 becomes high level. When the rotation speed of the blower 2 increases and Nist> KIN · Cov (9), the output of the fourth comparison circuit 80 becomes high level. In this way, the output of the AND gate 81 becomes high level, so that the contact 61a of the switch 61 becomes conductive and the contact 61a
b is cut off and a trip signal is output. Timer 83
Prevents an accidental change in the switching state of the switch 61 and transmission of a trip signal when the output of the AND gate 81 instantaneously becomes high level.

If the set time of the timer 83 is made sufficiently long, the coefficient multiplier 79
Can be omitted, but if it does so, it will be slow to stop the blower 2 when an abnormality occurs. Further, other values may be selected as the above-mentioned values Cov, Cmin, and values larger than these values may be selected, but the combinations of these values Cov, Cmin correspond to each other. You have to choose.

FIG. 10 is an electric circuit diagram of another embodiment of the present invention.
The signal indicating the rotation speed Nist of the blower 2 is a subtraction circuit 85.
A signal representing the actual wind speed Vist is given to the subtraction circuit 85 via the coefficient unit 86. Subtraction circuit 85
Is supplied to the absolute value circuit 87. The absolute value circuit 87 derives an output representing the absolute value of the signal given from the subtraction circuit 85 as shown in FIG. The comparator circuit 88 derives a high level signal of logic "1" when the output of the absolute value circuit 87 is equal to or greater than a predetermined value ER as shown in FIG. The output of the comparison circuit 88 is given to the timer 83 as in the above-described embodiment, and the timer 8 outputs the same.
The output of 3 controls the switch 61. The coefficient unit 86 derives by multiplying the actual wind speed Vist by the gain KN. When the present wind speed control device is normal, Nist = KN · Vist (10) is constantly established, the output of the comparison circuit 88 remains at the low level, and the contact 61b of the switch 61 is conductive. , The contact 61a is cut off, so that no trip signal is output.

For example, when the wind speed detecting means 7 fails, Nist> KN · Vist (11) Generally, when the signal representing the difference in the subtraction circuit 85 becomes a predetermined value ER or more, the comparison circuit 88 outputs a high level signal. It is derived and given to the timer 83, whereby the switch 6
The switching state of 1 changes, a trip signal is output, and the blower 2 stops. The timer 83 may be omitted.

Although the blower 2 is stopped by the trip signal in the above embodiment, the output of the setting circuit 84 may be set so that the blower 2 rotates at a low speed.

FIG. 13 is a block diagram of still another embodiment of the present invention. This embodiment is similar to the embodiment shown in FIG. 10 described above, and corresponding parts bear the same reference numerals. In this embodiment, the output of the subtraction circuit 85 is given to the absolute value comparison circuit 90. In the absolute value comparison circuit 90, as shown in FIG. 14, the absolute value of the difference output of the subtraction circuit 85 is the value ER.
When it is less than the above, a low level signal is derived, and when the absolute value of the difference output is greater than or equal to the value ER, a high level signal is derived. Other configurations are similar to those of the embodiment shown in FIG.

In order to stop the blower 2, the switch 61 is provided in the preceding stage of the motor drive circuit 41 in the above-mentioned embodiment, but as another embodiment of the present invention, as shown in FIG. The signal derived from 41 via line 88 may be blocked by the contact 92 of the relay 91. The coil of the relay 91 is excited when a high level signal is given from the timer 83, and the relay switch 92 is cut off.

Further, an alarm sound may be generated by driving a buzzer or the like by the output of the timer 83 or the AND gate 81, and an operator who hears the alarm sound shuts off the power source of the wind speed control device. Then, the wind tunnel equipment is stopped.

FIG. 16 is an overall system diagram of still another embodiment of the present invention, and FIG. 17 is a partial electric circuit diagram of the embodiment. This embodiment is similar to the previous embodiment, and corresponding parts bear the same reference numerals. It should be noted that in this embodiment, the pressure detecting means 94 for detecting the pressure is provided upstream of the main damper 5 and the bypass damper 21. The pressure detecting means 94 may be a so-called pressure switch, and the pressure switch 94 has an abnormally high pressure in the air duct 10, and the OR gate 65 in the embodiment shown in FIG. 1 is used. In the same situation in which the high level signal is derived from the
By switching from the state shown in FIG.
b is cut off, and thus the output from the full-open command value setting circuit 66 is given to the damper drive circuit 48. With such a configuration, the configuration is simplified as compared with the configuration using the first and second comparison circuits 63 and 64 and the OR gate 65. The pressure detecting means 94 may be realized not only by the pressure switch but also by another structure.

FIG. 18 is an overall system diagram of still another embodiment of the present invention, and FIG. 19 is a block diagram showing an electric configuration of a part of the embodiment shown in FIG. In this embodiment, the wind pipe 10 is provided upstream of the main damper 5 and the bypass damper 21.
A flow meter 96 is provided in the. The output of the flow meter 96 is given to the comparison circuit 97. The comparison circuit 97 is the first circuit described above.
In the same situation where a high level signal is derived from the OR gate 65 in the illustrated embodiment, the switch 62
The switching state of the flow meter 96
When the flow rate detected by the comparator circuit exceeds a predetermined value, the comparison circuit 97 gives the output from the full-open command value setting circuit 66 to the damper drive circuit 48 via the contact 62a that is in conduction. . Other configurations are the same as those in the above-mentioned embodiment. Such a configuration is also included in the spirit of the present invention.

As described above, according to the present invention, it is possible to prevent abnormally high speed rotation of the blower and undesired closing of the damper, which results in damage to the components of the wind tunnel, such as rupture of the wind pipe and damper. It is possible to prevent damage to the vehicle and prevent accidents resulting in injury or death. When an abnormality occurs, the blower is stopped to ensure safety.

[Brief description of drawings]

FIG. 1 is an overall electric circuit diagram of one embodiment of the present invention, FIG. 2 is an overall system diagram of one embodiment of the present invention, and FIG. 3 is a diagram illustrating the operation of the main damper 5 and the bypass damper 21. Figure for the
4 is a graph showing the characteristics of the function generating circuit 46, FIG. 5 is a graph showing the relationship between the speed of the vehicle 14, the opening θ of the main damper 5 and the rotation speed of the blower 2, and FIG. 32 is a graph showing the characteristics of 32, FIG. 7 is a graph showing the characteristics of the first comparison circuit 63 and the second comparison circuit 64, FIG. 8 is an electric circuit diagram showing the specific configuration of the limiting circuit 60, and FIG. 1) is a graph showing the characteristics of the third comparison circuit 77 and the fourth comparison circuit 80, and FIG. 9 (2) is the rotation speed Nist and the actual wind speed Vi.
FIG. 10 is a block diagram showing a part of the configuration of another embodiment of the present invention, and FIG. 11 is a characteristic diagram of the absolute value circuit 87 shown in FIG. FIG. 12 is a graph showing the characteristics of the comparison circuit 88, FIG.
FIG. 3 is a partial block diagram showing the electrical construction of another embodiment of the present invention, FIG. 14 is a graph showing the characteristics of the absolute value comparison circuit 90 of FIG. 13, and FIG. 15 is yet another of the present invention. 16 is a diagram showing a part of an electric circuit of the embodiment of the present invention, FIG. 16 is an overall system diagram of another embodiment of the present invention, and FIG. 17 is a part of an electrical configuration of the embodiment shown in FIG. 18 is a block diagram showing the whole system of another embodiment of the present invention, and FIG. 19 is a block diagram showing a part of the electric circuit of the embodiment shown in FIG. 1 ... Shear dynamo, 2 ... Blower, 3 ... Motor, 5,21 ... Damper, 6,9 ... Feed forward control circuit, 7 ... Wind speed detection means, 8 ... PI control circuit, 10 ... Wind pipe, 13 ... Measuring part, 14 ... Object to be tested, 60 ... Limiting circuit, 61, 62 ... Switch, 6
3, 64, 77, 80 ... Comparison circuit, 66 ... Full open command value generating circuit, 83 ... Timer, 84 ... Stop command value generating circuit, 94 ... Pressure detecting means, 96 ... Flowmeter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 57-149943 (JP, A) JP 59-69817 (JP, A)

Claims (6)

[Claims] 1. A wind speed control device for a wind tunnel, in which air from a blower is blown to an object to be tested through a wind pipe provided with a damper, a rotation speed detecting means for detecting a rotation speed of the blower, and a damper rather than a damper. The actual wind speed detecting means which is provided on the downstream side and detects the actual wind speed of the air blown out, and the rotation speed detected by the rotation speed detecting means are the first
And comparing the fact that the actual wind speed detected by the actual wind speed detecting means is greater than or equal to the second predetermined value. The wind speed control device for a wind tunnel, comprising: a second comparison unit that performs the above; and a unit that significantly changes the opening of the damper in response to the comparison output of at least one of the first and second comparison units. 2. A wind velocity control device for a wind tunnel, which blows air from a blower to an object under test through a wind pipe provided with a damper, which is provided upstream of the damper to detect pressure of air. Means and a comparing means for comparing and detecting that the pressure detected by the pressure detecting means exceeds a predetermined value, and the opening degree of the damper is greatly changed in response to the comparison output of the comparing means. And a wind speed control device for a wind tunnel. 3. A wind speed control device for a wind tunnel, which blows air from a blower to an object under test through a wind pipe provided with a main damper, wherein a bypass duct is provided upstream of the main damper. By installing a bypass damper linked to the main damper, and installing a flowmeter upstream of the main damper and the bypass damper, comparing that the flow rate detected by the flowmeter exceeds a predetermined value. A wind tunnel wind speed control device comprising: comparing means for detecting; and means for greatly changing the opening of the main damper in response to a comparison output of the comparing means. 4. A device for generating a command value of a rotation speed of a blower in a wind velocity control device of a wind tunnel, which blows air from a blower to an object to be tested through a wind pipe, and the command value, And a means for limiting to an upper limit value selected within a range less than a predetermined value that is equal to or higher than the maximum possible rotation speed of and that causes damage to the equipment, and the output of the limiting means is given to the blower. Wind tunnel wind speed control device. 5. A wind speed control device for a wind tunnel that blows air from a blower to an object to be tested through a wind pipe provided with a damper, and a rotation speed detecting means for detecting a rotation speed of the blower, and a damper. The actual wind speed detecting means which is provided on the downstream side and detects the actual wind speed of the air blown out, and the rotation speed detected by the rotation speed detecting means are the first
And comparing that the actual wind speed detected by the actual wind speed detecting means is less than the second predetermined value. A wind speed control device for a wind tunnel, comprising: a second comparing means for controlling the wind speed and a means for stopping the blower when the comparison outputs of both the first and second comparing means are obtained. 6. A wind speed control device for a wind tunnel, in which air from a blower is blown to an object to be tested through a wind pipe, the rotation speed detecting means for detecting a rotation speed of the blower, and the wind speed control means are provided downstream of the damper. An actual wind speed detecting means for detecting the actual wind speed of the blown air; a subtracting means for obtaining a difference between an output of the rotation speed detecting means and a normal rotation speed corresponding to the output of the actual wind speed detecting means; A wind speed controller for a wind tunnel, comprising means for stopping the blower when the absolute value of the difference is equal to or larger than a predetermined value in response to the output.